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Forward slips in the 9A

flightlogic

Well Known Member
Patron
This thread is a drift from the video of cross controlled approach that is being viewed by many.
I practiced a few forward slips the other day at about 80mph indicated. The RV does not really show much of an appreciable sink rate increase... when I have the rudder to the floor. If I let the airspeed decay (as tested with Ed Wischmeyer the other day) the sink rate can get away from you.
I used to love slipping the Luscombe, which had no flaps.
The RV shudders quite a bit... but does not give me much sink in a slip.
Am I missing a technique I should try? All comments welcome.
 
Am I missing a technique I should try?

Nah, the short wing models aren't much better...at least if you're accustomed to slipping antique/classic/aerobatic airplanes with lots of drag and powerful rudders. RVs are somewhat rudder limited compared to other types, and just don't have much drag to exploit in a slip.
 
one guys opinion

so I am no test pilot, but an observation or two.

If I am high on approach, full flap idle glide is VERY speed dependent.
not having calibrated it, something like -500 fpm at 70 kts, -600 at 65 kts, and -900 at 62 kts.!!!!! ( estimates)
the nose is pretty high, and it requires attention to hold that rate.

my forward slip is MUCH more nose down at 70 kts....and I can see my aim point on the runway, so that's the main benefit.
Left leg gets tired if I'm having to hold the slip for very long!....the big rudder really pushes back, and yes, there is bumping and rumbling as it's in the dirty air swirling behind the flaps I suppose....but it IS coming down at a good rate, or perhaps, a better angle?
 
I wonder how close to stall you are getting with full rudder at 62 kts? Not only does stall speed go up in sideslip, but the characteristics would be sporty i.e. that would be a spin entry - in what direction I don't know. I was always taught, by a very good pilot of aerobatic, antique and classic light planes (cubs, champs etc) that in a slip you always want to have the nose below the horizon - have lots of green in the windshield, not blue. He had lots of RV time as well, but I don't know if he intended that advise for the RVs as well. So really slowing it down and then putting in full rudder - I would want to try that up high first. Full disclosure I don't have much RV time yet.
 
Just right

This thread is a drift from the video of cross controlled approach that is being viewed by many.
I practiced a few forward slips the other day at about 80mph indicated. The RV does not really show much of an appreciable sink rate increase... when I have the rudder to the floor. If I let the airspeed decay (as tested with Ed Wischmeyer the other day) the sink rate can get away from you.
I used to love slipping the Luscombe, which had no flaps.
The RV shudders quite a bit... but does not give me much sink in a slip.
Am I missing a technique I should try? All comments welcome.

Somewhere between "not much sink" and "sink rate getting away from you " is the right speed for a slip. For me it's about 65 kts. This is one of the things I really like about the 9, you can slow down and sink like a rock or speed up and stretch your glide even into a stiff wind.
 
Not only does stall speed go up in sideslip, but the characteristics would be sporty i.e. that would be a spin entry... I was always taught, by a very good pilot of aerobatic, antique and classic light planes (cubs, champs etc) that in a slip you always want to have the nose below the horizon - have lots of green in the windshield, not blue.

I've never been able to spin an RV from a full deflection slip if you ease the stick all the way back. If you yank the stick sharply from high speed, you could snap/spin, but if you just simulate "creeping hand" syndrome from a full deflection slip, it's spin resistant. Most airplanes behave this way.
 
I've never been able to get the -9 to do anything interesting with full rudder deflection and the nose at the horizon or lower. It is useless to slip at too high of a speed where you'd be better off to slow down and get way behind the curve where it really starts to come down. I see it often "Why won't it come down?" "Because we're honkin' along at 70kts."
 
At about 60-65 KIAS (1.5 Vso) I think the -9 fwd slips full flaps very well. I do them all the time to make adjustments in the glide path.

What I do notice is that my airspeed doesn't read very well in full slips, so I have to do them a bit faster than my normal approach speed. If I aim for 60-65 KIAS in the slip, by the time I straighten out the airspeed is showing 55-60 KIAS which is approaching what I normally try to be doing short final at anyway.

In short, big fan of full flap fwd slips in the -9.
 
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9 model forward slips to land

Sounds like I need to try a few with slower speed. I know on most slips... kicking the nose straight at 50 feet settles the sink right back to normal for the round out.
If you hold an RV into a forward slip until that height... does it flatten out the glide path when you pop the nose into alignment with the runway?
I have tried simulations at altitude... but I just can't tell much. Not enough visual cues and references to be of much use.
I remember a thread where Allen of RV fame... let a Pax land. He got too slow and did not add power when told to. The gear got damaged.
I want the most performance, but don't want to tread in the danger zone.
Have not had any dual in the plane. Just bought it and taught myself.
 
Nick,
Do you have any aerobatic training? Maybe I am just freaked out because of watching how quickly the plane went around in the other video. I never wanted to do aerobatics but I have become very interested in getting some spin training in the future! I have no trouble slipping the 172 or Archer I am taking lessons in. When I do transition training, I sure want to master that skill before I try it myself!
 
what HE said....

Just to clarify, my comments were doing a STRAIGHT glide at 70, 65, 62kts.
( more sky at 62kts, but relatively flat attitude, lots of sink!)

when SLIPPING, due to the errors and margins desired, the nose is pointed at the runway, showing 70 kts on the ASI.

totally smarter to do a bunch of testing up high, and nail down the true speeds and any possible incipient stall conditions.
 
The airplane will not stall in a slip.....


The lower wing will not stall in a slip. It will be the top wing, and will pull you out of the slip on it's way to a spin entry if you fail to push and decrease the AOA.

But do try it for yourself....... at altitude of course.
 
My previous plane (Aeronca Sedan) had no flaps so slips have been in my bag of tricks for quite a while. My 9A doesn't slip as well as the Aeronca but it does work and I use them when I have to. It's a good skill to have for a lot of reasons. I keep the nose down and I fly no slower than 70 mph indicated when I slip.

I've never tried a cross controlled stall in the 9A and I'm not planning on it. However, somebody on another thread posted that his 9 went over the other way during a cross controlled stall just like Gasman said. There are some videos online that show the same thing in other aircraft. I would guess you'd have to be abusing things pretty bad to get this to happen but I don't know. If you keep the noise pointed down and maintain your speed there shouldn't be an issue at all. When you're done, remove the rudder pedal pressure and she swings back straight.
 
I routinely use a forward slip to lose altitude when needing a steeper approach path, or to make adjustments to altitude. The 9 slips reasonably well if it is done aggressively (not quite like some of the other RVs, but certainly is a useful maneuver). Depending on attitude and side of the slip, the indicated airspeed can vary, but I've not had any worries about a hard slip indicating ~65 mph going into it.

YMMV

Greg
 
While practicing slips today... I experimented with different angles and speeds. At no time did sink rate exceed 750. Any burst of power, and the rate would drop back to 450 very quickly. So, I will keep the trick up my sleeve for when I arrive too high and too fast. Did some upset training as well. The 9A rolls smartly around to the left and does not take long. I don't do aerobatics, but do wish to have some muscle memory available if I encounter a wake that rolls past 100 degrees or so. I that case, I would rather push the stick to lift the nose and keep the roll going. At no time did the G meter show more than positive 3 recorded today. My heart rate did exceed limits by a bit though....
 
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I've slipped a 4, an 8 and my 6. Forward slips in the short wing RVs just don't really seem to be all that dramatic to me either... Nothing like my old Cherokee 140 where I could really slip it and do the proverbial slam dunk approach with ease. I gave up on slipping the 6 to bleed off excess altitude and instead just slow it way down straight level and coordinated, then it'll drop like Wile E. Coyote riding an Acme anvil. That works better for me anyway. YMMV
 
Stall

Hi! My experience is that my RV4 can be induced to stall slipped/skidded/upside down/pointed straight down or straight up/and straight n level/right side up and down....I wonder if the safest way to approach your inquiry is to be above 3K agl, and stall in a slip (my plane lifts up and sits there) so you know what it indicates and then does...FYI: my slipped 4 with full rudder and flaps comes down like hard rain....very important to save some energy to round out lest you dig a smoking hole. But, you can really land on a spot....J
 
The -4 comes down like a brick with full flaps, full rudder slip and 70 kias. A stall (in this case a "cross control stall" also known as a "skidded turn stall")can be entered from any flight attitude, and at any speed. If it were to spin, it will spin in the direction of the rudder.
 
The -4 comes down like a brick with full flaps, full rudder slip and 70 kias. A stall (in this case a "cross control stall" also known as a "skidded turn stall")can be entered from any flight attitude, and at any speed. If it were to spin, it will spin in the direction of the rudder.

Your CS prop has more effect on descent rate than a slip in the -4.
 
As others have pointed out, the -9 doesn't slip well above 60 kts. Still I slip often and usually right around 60-65kts. I see around 500 fpm at 65 and 8-900 at 60. At 55kts it's generally pretty effective at slipping, just nothing like a Cessna where you can you peg the VSI.

Seems like discussing slips often leads to talk about the dreaded base-to-final stall. I think it's worth noting that the two are necessarily related. As the base to final scenario is produced in a "Skid" rather than a slip. See the FAA Airplane Flying Handbook 8-10 "Unlike skids, however, if an airplane in a slip is made to stall, it displays very little of the yawing tendency that causes a skidding stall to develop into a spin. The airplane in a slip may do little more than tend to roll into a wings level attitude. In fact, in some airplanes stall characteristics may even be improved."
 
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